Processing apparatus and gas supply method

ABSTRACT

A processing apparatus includes: a processing container configured to accommodate a substrate; a storage tank connected to the processing container via a gas supply pipe; a pressure sensor configured to detect a pressure in the storage tank; a valve provided in the gas supply pipe between the processing container and the storage tank; and a controller configured to control an opening degree of the valve based on the pressure in the storage tank detected by the pressure sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese PatentApplication No. 2021-040645, filed on Mar. 12, 2021, with the JapanPatent Office, the disclosure of which is incorporated herein in itsentirety by reference.

TECHNICAL FIELD

The present disclosure relates to a processing apparatus and a gassupply method.

BACKGROUND

A technique is known which takes a detection value of a pressure sensoron a secondary side of a processing container into a controller, andcontrols an amount of gas supplied into the processing container to makethe pressure inside the processing container become a constant pressure(see, e.g., Japanese Patent Laid-Open Publication No. 2017-179397).

SUMMARY

According to an aspect of the present disclosure, a processing apparatusincludes: a processing container configured to accommodate a substrate;a storage tank connected to the processing container via a gas supplypipe; a pressure sensor configured to detect a pressure in the storagetank; a valve provided in the gas supply pipe between the processingcontainer and the storage tank; and a controller configured to controlan opening degree of the valve based on the pressure in the storage tankdetected by the pressure sensor.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a processingapparatus according to an embodiment.

FIG. 2 is a view illustrating an example of a gas supply methodaccording to an embodiment.

FIG. 3 is a view illustrating results obtained from measuring a temporalvariation of a tank internal pressure.

FIG. 4 is a view illustrating results obtained from calculating an errorbetween a set discharge amount and an actual discharge amount.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The illustrativeembodiments described in the detailed description, drawings, and claimsare not meant to be limiting. Other embodiments may be utilized, andother changes may be made without departing from the spirit or scope ofthe subject matter presented here.

Hereinafter, non-limiting embodiments of the present disclosure will bedescribed with reference to the accompanying drawings. In all of thedrawings, the same or corresponding members or parts will be denoted bythe same or corresponding reference numerals, and overlappingdescriptions thereof will be omitted.

[Processing Apparatus]

An example of a processing apparatus of an embodiment will be describedwith reference to FIG. 1. FIG. 1 is a block diagram illustrating anexample of the processing apparatus of the embodiment.

The processing apparatus 1 includes, for example, a processing container10, a gas supply 20, an exhaust 30, and a discharge amount controller40.

The processing container 10 is a vertical container for accommodating aboat that holds substrates in a horizontal posture on multiple tiers inthe vertical direction, and performing a substrate processing. Theprocessing container 10 may be a container that accommodates a stage forplacing one or more substrates thereon, and performs a substrateprocessing. The substrate is, for example, a semiconductor wafer. Thesubstrate processing includes various types of processing for processinga substrate by supplying a processing gas into the processing container10, such as, for example, a film forming process and an etching process.The film forming process includes, for example, atomic layer deposition(ALD) and chemical vapor deposition (CVD).

The gas supply 20 includes, for example, a gas supply pipe 21, a gassource 22, a mass flow controller 23, a storage tank 24, and a furnaceopening valve 25.

The gas supply pipe 21 supplies a processing gas from the gas source 22into the processing container 10, and is connected to, for example, aninjector (not illustrated) that introduces the processing gas into theprocessing container 10. The mass flow controller 23, the storage tank24, and the furnace opening valve 25 are provided in this order from thegas source 22 in the middle of the gas supply pipe 21.

The gas source 22 supplies a processing gas into the storage tank 24 andthe processing container 10. The gas source 22 may be, for example, atank filled with a processing gas or a connection port to which aprocessing gas is supplied. The processing gas includes, for example, araw material gas used for the film forming process and an etching gasused for the etching process.

The mass flow controller 23 measures the mass flow rate of theprocessing gas supplied from the gas source 22 and stored in the storagetank 24, to control the flow rate.

The storage tank 24 stores a processing gas, and is provided to supply alarge amount of processing gas into the processing container 10 in ashort time. The storage tank 24 temporarily stores the large amount ofprocessing gas, and supplies the processing gas into the processingcontainer 10 at once in a short time, so that the large amount ofprocessing gas may be supplied in a short time. The storage tank 24 isalso referred to as a buffer tank.

An electropneumatic regulator 44 to be described later controls theopening degree of the furnace opening valve 25. By controlling theopening degree of the furnace opening valve 25, the discharge amount ofthe processing gas supplied from the storage tank 24 into the processingcontainer 10 is controlled.

The exhaust 30 includes, for example, an exhaust pipe 31, an exhaustvalve 32, and an exhaust device 33.

The exhaust pipe 31 exhausts the processing gas in the processingcontainer 10, and is connected to, for example, an exhaust port (notillustrated) of the processing container 10. The exhaust valve 32 andthe exhaust device 33 are provided in this order from the side of theprocessing container 10 in the middle of the exhaust pipe 31.

The exhaust valve 32 adjusts the exhaust amount of the processing gasthat flows through the exhaust pipe 31. The exhaust valve 32 may be, forexample, an automatic pressure controller (APC) valve.

The exhaust device 33 evacuates the inside of the processing container10 through the exhaust pipe 31. The exhaust device 33 includes, forexample, a vacuum pump such as a dry pump or a turbo molecular pump.

The discharge amount controller 40 controls the discharge amount of theprocessing gas supplied from the storage tank 24 into the processingcontainer 10. The discharge amount controller 40 includes, for example,a pressure sensor 41, a controller 42, an input device 43, and theelectropneumatic regulator 44.

The pressure sensor 41 is provided in the storage tank 24. The pressuresensor 41 detects the pressure inside the storage tank 24 (hereinafter,also referred to as a “tank internal pressure”), and outputs theobtained detection value to the controller 42.

The controller 42 is configured to perform an arithmetic processingincluding a control. The controller 42 may be, for example, a computer.The controller 42 is configured to control the opening degree of thefurnace opening valve 25 via the electropneumatic regulator 44, based onthe detection value of the pressure sensor 41. The controller 42 may beconfigured to control the opening degree of the furnace opening valve 25without using the electropneumatic regulator 44.

The input device 43 enables, for example, an operator to input varioustypes of information. The various types of information include, forexample, the discharge amount of the processing gas desired to besupplied from the storage tank 24 into the processing container 10. Thedischarge amount of the processing gas is specified by, for example, apressure value. Hereinafter, the specified pressure value will bereferred to as a set discharge pressure. The input device 43 may beincluded in, for example, an apparatus controller that controls theentire processing apparatus 1, or may be a computer provided separatelyfrom the apparatus controller.

The electropneumatic regulator 44 controls the opening degree of thefurnace opening valve 25 using a pneumatic pressure based on a command(electric signal) from the controller 42.

[Gas Supply Method]

Referring to FIG. 2, descriptions will be made on a case where a filmformation is performed through the ALD that deposits a film byintermittently supplying a processing gas into the processing container10, as an example of the gas supply method of the embodiment. FIG. 2 isa view illustrating an example of the gas supply method of theembodiment, and represents a temporal variation of the tank internalpressure when the processing gas is intermittently supplied from theinside of the storage tank 24 into the processing container 10. In FIG.2, the horizontal axis represents time, and the vertical axis representsthe tank internal pressure [Torr].

In the following, it is assumed that the substrate is accommodated inthe processing container 10, and the processing gas is stored in thestorage tank 24 such that the tank internal pressure becomes 290 Torr atthe time when the gas supply method is started. Further, it is assumedthat 280 Torr is input as the set discharge pressure through the inputdevice 43 by, for example, the operator prior to the start of the gassupply method.

First, the controller 42 transmits a command to the electropneumaticregulator 44 to open the furnace opening valve 25. Based on the command,the electropneumatic regulator 44 opens the furnace opening valve 25. Asa result, a first supply of the processing gas from the inside of thestorage tank 24 into the processing container 10 is started, and thetank internal pressure starts to decrease from 290 Torr.

When the first supply of the processing gas is started, the controller42 controls the furnace opening valve 25 in a variable opening degreemode. The variable opening degree mode refers to a mode for controllingthe opening degree of the furnace opening valve 25 such that the dropamount of the tank internal pressure becomes equal to the set dischargepressure in a predetermined time. The drop amount of the tank internalpressure is calculated by subtracting the detection value of thepressure sensor 41 in a state where the furnace opening valve 25 isopened, from the detection value of the pressure sensor 41 before thefurnace opening valve 25 is opened. In the example of FIG. 2, thecontroller 42 controls the opening degree of the furnace opening valve25 such that the drop amount of the tank internal pressure becomes equalto the set discharge pressure of 280 Torr, that is, the tank internalpressure becomes 10 Torr (290 Torr-280 Torr), in a predetermined timet1.

After the predetermined time elapses, the controller 42 transmits acommand to the electropneumatic regulator 44 to close the furnaceopening valve 25. Based on the command, the electropneumatic regulator44 closes the furnace opening valve 25. As a result, the first supply ofthe processing gas from the inside of the storage tank 24 into theprocessing container 10 is stopped. Further, the controller 42 controls,for example, an opening/closing valve (not illustrated) or the mass flowcontroller 23 interposed between the gas source 22 and the storage tank24, to supply the processing gas from the gas source 22 into the storagetank 24 and store the processing gas in the storage tank 24. In theexample of FIG. 2, the processing gas is stored in the storage tank 24until the tank internal pressure reaches 300 Torr.

Next, the controller 42 transmits a command to the electropneumaticregulator 44 to open the furnace opening valve 25. Based on the command,the electropneumatic regulator 44 opens the furnace opening valve 25. Asa result, a second supply of the processing gas from the inside of thestorage tank 24 into the processing container 10 is started, and thetank internal pressure starts to decrease from 300 Torr.

When the second supply of the processing gas is started, the controller42 controls the furnace opening valve 25 in the variable opening degreemode. In the example of FIG. 2, the controller 42 controls the openingdegree of the furnace opening valve 25 such that the drop amount of thetank internal pressure becomes equal to the set discharge pressure of280 Torr, that is, the tank internal pressure becomes 20 Torr (300Torr-280 Torr), in the predetermined time t1.

After the predetermined time elapses, the controller 42 transmits acommand to the electropneumatic regulator 44 to close the furnaceopening valve 25. Based on the command, the electropneumatic regulator44 closes the furnace opening valve 25. As a result, the second supplyof the processing gas from the inside of the storage tank 24 into theprocessing container 10 is stopped. Further, the controller 42 controls,for example, an opening/closing valve (not illustrated) or the mass flowcontroller 23 interposed between the gas source 22 and the storage tank24, to supply the processing gas from the gas source 22 into the storagetank 24 and store the processing gas in the storage tank 24. In theexample of FIG. 2, the processing gas is stored in the storage tank 24until the tank internal pressure reaches 305 Torr.

Then, the controller 42 performs third and subsequent supplies of theprocessing gas in the same manner as that for the first and secondsupplies of the processing gas. In the third supply of the processinggas, the controller 42 controls the opening degree of the furnaceopening valve 25 such that the drop amount of the tank internal pressurebecomes equal to the set discharge pressure of 280 Torr, that is, thetank internal pressure becomes 25 Torr (305 Torr-280 Torr), in thepredetermined time. In the fourth supply of the processing gas, thecontroller 42 controls the opening degree of the furnace opening valve25 such that the drop amount of the tank internal pressure becomes equalto the set discharge pressure of 280 Torr, that is, the tank internalpressure becomes 20 Torr (300 Torr-280 Torr), in the predetermined time.

Then, the supply of the processing gas is performed a set number oftimes, so that a film having a desired film thickness is deposited onthe substrate. The set number of times is determined by, for example,recipes.

In the film formation by the ALD in the processing apparatus 1, theuniformity of film thickness among devices may be deteriorated by adeviation or aging of hardware such as, for example, the storage tank24, the furnace opening valve 25, the exhaust valve 32, the exhaustdevice 33, and the injector. It is believed that this is because thesupply amount of the processing gas from the inside of the storage tank24 into the processing container 10 is unstable due to the variation oraging of hardware.

As an example of a method of stabilizing the supply amount of theprocessing gas into the processing container, there is a method of usinga furnace inlet valve in which a CV value is strictly controlled.However, this method has a limit in product yield.

As another example of the method of stabilizing the supply amount of theprocessing gas into the processing container, there is a method oftaking a detection value of a pressure sensor provided on a secondaryside of the processing container into the controller, and controllingthe supply amount of the processing gas such that the detection valuebecomes constant every time. However, in this method, a quick andprecise control is difficult because due to the processing containerdisposed between the storage tank and the pressure sensor, a time lagoccurs until the detection value of the pressure sensor is obtainedafter the processing gas is supplied from the storage tank into theprocessing container.

According to the gas supply method of the embodiment, the controller 42controls the opening degree of the furnace opening valve 25 based on thedetection value of the pressure sensor 41 that monitors the pressure inthe storage tank 24. That is, the controller 42 directly controls thesupply amount itself of the processing gas supplied from the inside ofthe storage tank 24 into the processing container 10. Thus, the supplyamount of the processing gas into the processing container 10 may becontrolled quickly and precisely. As a result, the pressure in theprocessing container 10 may also be precisely controlled.

According to the gas supply method of the embodiment, when the furnaceopening valve 25 is opened, the controller 42 controls the openingdegree of the furnace opening valve 25 such that the drop amount of thetank internal pressure becomes equal to the set discharge pressure inthe predetermined time. As a result, the processing gas having the setdischarge pressure may be supplied from the inside of the storage tank24 into the processing container 10 in the predetermined time, so thatthe same amount of processing gas may be supplied into the processingcontainer 10 every time for the film formation by the ALD. As a result,the uniformity of film thickness is improved.

In the embodiment described above, the controller 42 controls thefurnace opening valve 25 in the variable opening degree mode immediatelyafter the furnace opening valve 25 is opened. However, the presentdisclosure is not limited thereto. For example, the controller 42 maycontrol the furnace opening valve 25 in a fixed opening degree modeuntil a predetermined time elapses after the furnace opening valve 25 isopened, and may control the furnace opening valve 25 in the variableopening degree mode thereafter. The fixed opening degree mode refers toa mode for fixing the furnace opening valve 25 to a constant openingdegree. For example, when the opening degree of the furnace openingvalve 25 is set to be large in the fixed opening degree mode, a largeamount of processing gas may be supplied from the inside of the storagetank 24 into the processing container 10 in a short time immediatelyafter the furnace opening valve 25 is opened, so that the supply amountof the processing gas may be precisely adjusted in the remaining time.

EXAMPLES

Examples in which the gas supply method of the embodiment was performedwill be described with reference to FIGS. 3 and 4. In the Examples, thefurnace opening valve 25 was controlled in the fixed opening degree modeuntil a predetermined time (0.5 seconds) elapsed after the furnaceopening valve 25 was opened, and controlled in the variable openingdegree mode after the predetermined time elapsed. The sum of the timeduring which the furnace opening valve 25 was controlled in the fixedopening degree mode and the time during which the furnace opening valve25 was controlled in the variable opening degree mode was set to threeseconds. Further, the Examples were performed under five Conditions A toE which were different from each other in combination of the tankinternal pressure before the furnace opening valve 25 was opened(hereinafter, referred to as the “tank internal pressure during thestorage”) and the set discharge pressure. In the Examples, theevaluation was performed using nitrogen gas, instead of the processinggas.

For Condition A, the tank internal pressure during the storage was setto 380 Torr, the set discharge pressure was set to 300 Torr, and atarget tank internal pressure was 80 Torr (380 Torr-300 Torr).

For Condition B, the tank internal pressure during the storage was setto 360 Torr, the set discharge pressure was set to 300 Torr, and thetarget tank internal pressure was 60 Torr (360 Torr-300 Torr).

For Condition C, the tank internal pressure during the storage was setto 310 Torr, the set discharge pressure was set to 290 Torr, and thetarget tank internal pressure was 20 Torr (310 Torr-290 Torr).

For Condition D, the tank internal pressure during the storage was setto 340 Torr, the set discharge pressure was set to 310 Torr, and thetarget tank internal pressure was 30 Torr (340 Torr-310 Torr).

For Condition E, the tank internal pressure during the storage was setto 300 Torr, the set discharge pressure was set to 280 Torr, and thetarget tank internal pressure was 20 Torr (300 Torr-280 Torr).

FIG. 3 is a view illustrating results obtained from measuring thetemporal variation of the tank internal pressure. In FIG. 3, thehorizontal axis represents time [seconds], and the vertical axisrepresents the tank internal pressure [Torr]. In FIG. 3, a solid line, adotted line, a dashed line, an alternate long and short dashes line, andan alternate one long and two short dashes line represent results ofConditions A to E, respectively.

As illustrated in FIG. 3, it may be seen that in all of Conditions A toE, the tank internal pressure significantly drops immediately after thefurnace opening valve 25 is opened, and then, stabilizes at the targettank internal pressure. This result represents that a large amount ofprocessing gas may be supplied from the inside of the storage tank 24into the processing container 10 in a short time immediately after thefurnace opening valve 25 is opened, and the supply amount of theprocessing gas may be adjusted precisely in the remaining time.

FIG. 4 is a view illustrating results obtained from calculating an errorbetween the set discharge amount and the actual discharge amount. FIG. 4represents the condition, the tank internal pressure during the storage[Torr], the target tank internal pressure [Torr], the set dischargeamount (set discharge pressure) [Torr], the actual discharge amount(actual discharge pressure) [Torr], and the error (the actual dischargeamount—the set discharge amount) [Torr] in this order from the leftcolumn.

As illustrated in FIG. 4, it may be seen that in all of Conditions A toE, the error between the actual discharge amount and the set dischargeamount is less than 2 Torr. This result represents that the supplyamount of the processing gas from the inside of the storage tank 24 intothe processing container 10 may be precisely adjusted in all ofConditions A to E.

According to the present disclosure, the supply amount of the processinggas into the processing container may be precisely adjusted.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. A processing apparatus comprising: a processingcontainer configured to accommodate a substrate; a storage tankconnected to the processing container via a gas supply pipe; a pressuresensor configured to detect a pressure in the storage tank; a valveprovided in the gas supply pipe between the processing container and thestorage tank; and a controller configured to control an opening degreeof the valve based on the pressure in the storage tank detected by thepressure sensor.
 2. The processing apparatus according to claim 1,wherein the controller is configured to control the opening degree ofthe valve to make a drop amount of the pressure in the storage tankbecome equal to a set discharge pressure.
 3. The processing apparatusaccording to claim 2, further comprising: an input device configured toinput the set discharge pressure.
 4. The processing apparatus accordingto claim 2, wherein the controller controls the opening degree of thevalve in a first mode for fixing the valve to a constant opening degree,and subsequently, controls the opening degree of the valve in a secondmode for controlling the opening degree of the valve to make the dropamount of the pressure in the storage tank become equal to the setdischarge pressure.
 5. The processing apparatus according to claim 1,wherein the storage tank stores a raw material gas.
 6. The processingapparatus according to claim 1, wherein the controller is configured toperform a film formation by an atomic layer deposition (ALD) thatdeposits a film by intermittently supplying a gas from an inside of thestorage tank into the processing container, and control the openingdegree of the valve based on the pressure detected by the pressuresensor when the gas is supplied into the processing container.
 7. A gassupply method comprising: storing a gas in a storage tank connected to aprocessing container via a gas supply pipe; and supplying the gas storedin the storage tank into the processing container, wherein a valve isprovided in the gas supply pipe between the processing container and thestorage tank, and in the supplying, the opening degree of the valve iscontrolled based on a pressure in the storage tank.
 8. The gas supplymethod according to claim 7, wherein, in the supplying, the openingdegree of the valve is controlled to make a drop amount of the pressurein the storage tank become equal to a set discharge pressure.
 9. The gassupply method according to claim 7, wherein, in the supplying, theopening degree of the valve is controlled in a first mode for fixing thevalve to a constant opening degree, and subsequently, controlled in asecond mode for controlling the opening degree of the valve to make thedrop amount of the pressure in the storage tank become equal to the setdischarge pressure.